The objectives of the research proposed here are (a) to investigate the problem of the perceptual reversal of ambiguous figures and displays (b) to demonstrate that, without knowledge of the reversibility of such figures, observers tend to maintain their initial perception rather than to change it (c) to determine whether the same tendency holds for unbiased ambiguous figures and displays (d) to analyze what factors are responsible for reversal by knowledgable observers (e) to examine whether satiation or novelty-seeking is a determinant of reversal and (f) to investigate the possibility that reversal occurs by a process of default. Several methods of investigating these questions will be employed, in particular a newly devised procedure for obtaining data on reversal without specifically informing subjects of the figure's reversibility. Some of the well-known ambiguous figure-ground and reversible perspective figures will be studied but various new unbiased figures will also be investigated. Previously used methods for testing the satiation theory will be modified in line with the objectives cited above. The hypotheses guiding this investigation are as follows: (1) There is a tendency to maintain a given perception of an ambiguous figure. (2) Reversal will occur, if (a) the observer is actively searching for alternatives, (b) is intentionally attempting to reverse, (c) is informed about the alternatives so that competing interpretations are highly available, (3) Reversal can also be the result of default where attention lapses or the observer loses track of a particular perception, (4) Reversal is not caused by satiation and the effects that seem to support such a theory result from demand characteristics of experiments entailing knowledge of reversibility.